namespace ensemble objects - see NEM's Using namespace ensemble without a namespace (in fact, it uses ::). RS hacked together this little candybox as a variation on that page:
namespace eval neo {variable version 0.1}
proc neo::new {name _where_ args} {
set map [dict create]
foreach {slot = value} $args { dict set map $slot $value }
namespace ensemble create -command $name -map $map
}
proc neo::slot {object slot = command args} {
set map [namespace ensemble configure $object -map]
dict set map $slot [linsert $args 0 $command]
namespace ensemble configure $object -map $map
}
proc neo::method {object name params body} {
set params [linsert $params 0 self]
slot $object $name = ::apply [list $params $body ::] $object
}
proc neo::const val { return $val }
interp alias {} neo::config {} namespace ensemble configure
proc neo::delete name {rename $name {}}#-- So far for neo the "system", the rest is tests and demos:
proc rect {canv x0 y0 x1 y1} {
set id [$canv create rect $x0 $y0 $x1 $y1]
set obj [neo::new $canv.rect$id where \
id = [list const $id] \
coords = [list ::$canv coords $id]]
neo::slot $obj canvas = const $canv
set obj
}
catch {destroy .c} ;# good for repeated sourcing
pack [canvas .c]
set r [rect .c 20 20 100 100]
puts "id = [$r id], coords = [$r coords]"
neo::slot $r type = const "rectangle" ;#-- object-specific slot
puts "$r is a [$r type]"
neo::method $r width {} {
lassign [$self coords] x0 y0 x1 y1
expr {abs($x1-$x0)}
}
neo::method $r height {} {
lassign [$self coords] x0 y0 x1 y1
expr {abs($y1-$y0)}
}
puts height:[$r height],width:[$r width]
neo::method $r area {} { expr {[$self width] * [$self height]} }
puts "area = [$r area]"
puts [neo::config $r -map]